Although oxygen is essential for life, its reactivity with other compounds can be detrimental. Free radicals are the result of some oxygen molecules that are converted into oxidizing agents during the process that creates energy in cells, cellular respiration. Oxygen is a very active element, and in the process of exchanging the molecules in the bloodstream, oxygen combines with many different compounds. Some of the compounds can cause damage to body tissue.

These harmful compounds, "free radicals", can be caused in a number of ways, such as ionized radiation from the sun, x-rays, and industry; nitrous oxide from automobile exhaust, cigarette smoke, alcohol, saturated fat, and chemicals found in food, water, and air. Because of free radicals´ instability, they react with cells in the body causing abnormality.

Antioxidants work in a variety of ways to reduce the effects of free radicals.* They may greatly decrease the damage caused by free radicals, stop them from forming to begin with, or "oxidize" them by combining with them and neutralizing their harmful effects through stabilization.* The body produces two enzymes on its own to stabilize free radicals. They are Superoxide dismutase (SOD), catalase, and glutathione peroxidase. Although supplements of these enzymes are available directly, the body may not be able to absorb them.* Therefore, it is much more useful to supply the body with the building blocks of these enzymes so that the body can build them itself. There are many vitamins, minerals, enzymes, and herbs that act as antioxidants or aid in the production of them such as Pine Bark Extract, vitamin E, beta-carotene, vitamins B2, B3, and B6, CoEnzyme Q-10, bilberry, grape seed, pine bark, ginkgo biloba, selenium, zinc, copper, and many others.* The best way to make sure your covering all the bases in the neutralization of free radicals is to supplement with a wide variety of antioxidants.* Many supplements have been developed containing a blend of antioxidants.